A. Field of the Invention
The present invention relates to a multi-stage pump, particularly adapted to operate in bore holes of relatively small width and able to operate effectively against a varying magnitude of pressure head.
B. Brief Description of the Prior Art
A typical reciprocating pump utilizes a reciprocating piston which on an intake stroke causes a flow of water through a check valve into a pumping chamber, and on a discharge stroke moves the fluid from the pumping chamber along the desired flow path. Pumps of this general type have been arranged in multi-stage assemblies, such as that shown in U.S. Pat. No. 1,844,261, Penrod. In that patent, the several pumping units are arranged in end to end relationship, and the several pistons of the pumping units are rigidly interconnected with one another to operate in unison. Thus, the lower or downstream side pumping units experience lesser back pressure, while the uppermost pumping unit experiences the full back pressure against which the pumping assembly operates.
Also, there are known in the prior art various devices which utilize electric power to activate a solenoid to cause a pumping action. Such a device is shown in the Kato et al patent, U.S. Pat. No. 2,788,170, this particular device being adapted for use as an aquarium pump. Representative of yet another pumping configuration is the Hasquenoph et al patent, U.S. Pat. No. 3,514,221.
While there are a wide variety of prior art pumps especially adapted for specialized applications, there is a continuing need for improvement in such pump designs. Accordingly, it is an object of the present invention to provide a multi-stage pump which is quite simple in its basic operating components and its overall configuration, is able to fit in a relatively small diameter hole, is able to operate on a fluid which contains abrasive particles (such as well water having small particles of sand therein) and is able to operate either at a high volumetric flow rate against lower pressure head or at lower volumetric flow rates at higher pressure heads.